The longer Piers Morgan continues to milk this, and release drips and drabs, the better ETH looks. Considering the amount of bile that Ronaldo has held in his heart/spewed since pre-season, ETH has handled him impeccably. He's publicly supported him and given him enough rope for him to hang himself, which he has done in spectacular fashion.
Last season, Ole bent the team around Ronaldo's best interests, and while he scored a decent amount of goals, the team suffered. ETH has done the opposite, and the side is playing much much better, and its Ronaldo's stats that have suffered. His ego can't handle that and he is lashing out against everyone and anyone like the petulant child that he is.
I struggle to think of his motivation for this interview, that he's been desperate to give since the summer. One would think that he's mature enough to realize that this is a bad idea, or at the very least, his people/Mendes are savvy enough to advise him properly. It all can't just be petulance, can it? He apparently wants a move to a CL club so he can protect his CL goal tally. Nobody is touching him after this. Did he realize that after no suitors could be found this summer and he's just going out in a blaze of glory?
He makes anywhere from $1.6m - $2.3m per Instagram post (depending on which website you believe). United supporters don't matter to him or his brand. Ronaldo FC supporters do, and those muppets are lapping up every word he spews forth. If he can keep those people engaged and supportive, he continues to be relevant and can cash in on his popularity. Maybe that's his thinking?